Field of the Invention
The present invention relates to an automatic steering control apparatus that controls a steering amount of a vehicle so that the vehicle travels following a target trajectory.
Description of the Background Art
Automatic steering control apparatuses have been proposed which determine a target trajectory with reference to, for example, a traveling trajectory of a preceding vehicle or a centerline of a road and allow a subject vehicle to travel following the determined target trajectory. For example, Japanese Patent Application Laid-Open No. 2015-77908 discloses an automatic steering control apparatus that allows a subject vehicle to travel more accurately following a target trajectory even when a forward direction of the car body of the subject vehicle does not coincide with its traveling direction due to a sideslip of the subject vehicle, etc.
Predetermining a target trajectory allowing the subject vehicle to follow is a precondition for such an automatic steering control apparatus. Until determining a target trajectory, the apparatus will have difficulties in controlling steering without any target trajectory, for example, upon start of the automatic steering control. Thus, disturbances such as the steering by the driver before starting the steering control through a control input may increase a difference between a position of the subject vehicle and a target trajectory which is measured after start of the steering control through the control input, and cause abrupt change in the behavior of the subject vehicle.